A staple cartridge for use with a surgical stapler can comprise a cartridge deck and a plurality of staples at least partially positioned within the cartridge deck. In various embodiments, the staples can comprise legs which extend upwardly from the deck wherein the deck can further include supports, or guides, which are configured to hold the staple legs in a particular alignment. In at least one such embodiment, the staple legs can extend upwardly from the supports into a tissue thickness compensator.